Apparatus for welding interrupted seams

ABSTRACT

Welding apparatus is traversed along a weld gap to be welded, from one interruption of the required weld seam to another such interruption. Incident thereto, the apparatus is manipulated so that near the first interruption the weld arc is in trailing position but near the second interruption it is in leading position relative to the welding apparatus.

United States Patent 11 1 Ploetz et al.

[ Dec. 25, 1973 APPARATUS FOR WELDING INTERRUPTED SEAMS Inventors:Ulrich Ploetz,

Rostock-Warnemunde; Wolfgang Thiesen, Rostock, both of Germany VEBIngenieurburo Schiffbau, Rostock-Osthafen, Germany Filed: July 9, 1971Appl. No.: 161,004

Assignee:

US. Cl 219/130, 219/125 R, 219/137 Int. Cl B23k 9/00 Field of Search219/137, 130, 136,

References Cited UNITED STATES PATENTS 3/1958 Tiedemann 219/125 R3,522,410 8/1970 Benfield 219 130 1,933,340 10/1933 Raymond...

1,884,645 10 1932 Ford 1,539,383 5/1925 Bienenstok 219/125 R PrimaryExaminer-C. L. Albritton Assistant Examiner-George A. Montanye AtrornevAlbert C. Nolte, Jr. et al.

[57] ABSTRACT Welding apparatus is traversed along a weld gap to bewelded, from one interruption of the required weld seam to another suchinterruption. Incident thereto, the apparatus is manipulated so thatnear the first interruption the weld arc is in trailing position butnear the second interruption it is in leading position relative to thewelding apparatus.

4 Claims, 7 Drawing Figures 2s PATENTEUUEC :975 gm 1 of 3 FIG! FIG. 2

INVENTORS ULRICH PLOETZ WOLFGANG THIESEN BY 7&5; f 7&41

' ATTORNEYS PATENTED was 1975 SHEEYZUFB INVENTORS ULRICH PLOETZ WOLFGANGTHIESEN BY X i 75% FIG-4 ATTORNEYS FIG. 7

INVENTORS ULRICH PLOETZ WOLFGANG THIESEN .BY 77%; 5 7M:

ATTORNEYS PATENTEB DEC 2 5 2973 1 APPARATUS FOR WELDING INTERRUPTEDSEAMS BACKGROUND AND NATURE OF THE INVENTION I-Ieretofore greatdifficulty has been encountered, particularly in the construction ofships, when it was necessary to weld long seams interrupted bystructural elements, c'ross-seams and the like. Ordinary fullautomaticwelding techniques were unable to produce the entire seam under suchconditions, and special semi-automatic methods, known up to now, were inno position to produce such an entire seam effectively or economically.Therefore hand welding was used, particularly at the end points orinterrruptions of such a seam, but the combined or frequentlyalternating uses of hand welding and of (full or semi-) automaticwelding was unattractive. This applied particularly when the automaticwelding was done with relatively heavy apparatus, which however wasneeded for desirable shielded-arc procedures and the like.

The invention enables an automatic welding device to operate frombeginning to end of an interrupted weld seam, without assistance of handwelding and the like, and with full use of shielded arc nozzles andother auxiliaries. The invention achieves this by manipulating theautomatic welding apparatus so that at the beginning of the interruptedseam (near a first cross-profile or the like) the arc is in trailingposition after the apparatus itself but thereafter, near the end of theinterrupted seam (near a second cross-profile or the like) the arc is inleading position.

DRAWINGS FIG. 1.

FIGS. 6 and 7 are views taken along lines -5 in FIG. 1 to show differentforms of apparatus and structure involved in performance of the newmethod or forming part of the new apparatus.

DETAILED DESCRIPTION Referring basically to FIGS. 1 and 5: A profile lis welded to plate 2, between corners a and b, by continuous straightfillet weld seam S. Thus far it was one of the main problems that theflange 1F of profile l interfered with normal or desirable electrodepositions, such as indicated in broken lines in the area of flange 1Fand in the corners under flanges 3F (FIG. 4, said corners being shown inFIG. 1 at a and b).

According to the invention this problem is overcome by so manipulatingapparatus 4 as to orient it consecutively in initial position 4A,wherein the welding tip T and nozzle N are trailing relative to thewelding traverse directions shown by an arrow in FIG. 1; intermediatepositions 48; and ultimate position 4C wherein the tip and nozzle areleading. I

For this purpose guide tracks 7 and 8 are provided between consecutivecross girders 3 and laterally adjacent the projected seam, and weldingapparatus 4 has a guide unit so engaging the two specially curved tracksas to produce these changes of orientation incident to the traversingmotion. As schematically shown in FIG. 5, track 7 is engaged by guiderollers 9, while double track 8 is contacted by guide pin 10. Theseguide rollers and guide pin are mounted at a fixed distance from oneanother on undercarriage 4 whereon welding apparatus 4 is longitudinallybut not transversely slidable, and means are provided to keep thisapparatus at predetermined distance from the work area, for example byfeeler 4" (FIG. 6) and feeler control apparatus (not shown). Theposition and orientation of automatic welder 4 also determines thepositions and orientations of nozzle N and electrode supply E thereof.The curvature of tracks 7, 8, required for these effects, can bedetermined empirically or mathematically or by combined empirical andmathematical methods, as will be understood on consideration hereof.

It will be understood that welder 4 and its electrode E and nozzle aretraversed along the corner between straight profile l and plate 2. Thewelding apparatus 4 can hold the welding tip in fixed position or canoscillate it transversely (t in FIG. 5) or longitudinally up and down 1in FIG. 5). The transverse oscillation 2 enables the device for exampleto produce a fillet weld seam S of suitable curvature in a verticalplane. The longitudinal electrode motions l cooperate with the motionsof the welder 4 on it curved tracks to keep the welding are on thestraight seam S.

By the guide means and auxiliary apparatus of FIGS. 1, 2 and 5, the newapparatus is enabled to perform the desired welding operation from pointa underneath a first crossing of profile flanges 1F, to theaforementioned point b under a second flange crossing symmetricallylocated relative to the first. It will be understood that, instead ofreorienting the entire welding apparatus as in FIG. 1, it is alsopossible to produce different orientations of the weld top T relative tothe welding apparatus 4, some of which are exemplified by FIGS. 6 and 7.

Guide tracks 7 and 8 can either be clamped or bolted or tack-welded tothe aggregate of plate 2 and profiles 3, depending on whether use ismade of heavy welding apparatus 4 with control means enabling it toperform a great variety of manipulations and weld tip operations, orwhether a relatively light device is used which the worker can manuallycarry from one workside to the next, and several of which (for exampleas in FIG. 1) a single worker can supervise, as they operate indifferent cells 1 2 3.

The devices can also be varied with respect to details of their guidemechanism. For example:

FIG. 2 shows a system wherein the aforementioned guide tracks 7, 8 aremounted on a portable plate 5, held at predetermined distance fromprofile l by rods 6. A track and support unit of this kind can becarried and installed by one or two workers on relatively small jobs.

FIG. 3 shows a modified system wherein a straight guide rod 11 extendsalong profile I, being spaced therefrom for example by plate 11'. Rod 11may have teeth 12 engaged by gears 12' in guide unit 13 whereon weldingapparatus 4 is angularly and longitudinally shiftable. A pinion 14engaging rod 11 and driving control gear with radial arm 15' can beused, with the aid of clutch or control mechanism (not shown) to slideand swing welder 4 0n unit 13 in such a way that welding tip 16traverses longitudinally along profile 1, at uniform distance therefrom,while the positions and orientations of the welder are changed as shown.

Still another guide unit 17 is shown in FIG. 4, wherein straight edgemember 18 has curved ends 18' and is engaged by guiding unit 19 whichsupports welding apparatus 4. Also provided is a control unit 20interposed between guide unit 19 and welder 4. This control unit caninclude a portable guide track 22. In response to traversal fromstraight track 18 to curved track 18, the control unit swings portableguide track 22 into progressively deflected positions as shown, andthereby causes progressive swinging and sliding motions of welder 4 onunit 19, as also shown, by means of a mechanism which obviously can bedeveloped by -persons skilled in the art, in the light of thisdisclosure,

to move welding nozzle 21 through the desired positions andorientations, unimpeded by flanges 1F and BF of the profile members. Itwill further be seen that longitudinal track 18 obviously can becomposed of any desired numbers of individual elements, suitablyinterconnected endwise, or can telescope to desired length between thelimiting profiles.

What is claimed is:

1. An arc welder for welding a workpiece with a seam to be weldedextending in a single plane and abutted at each end of the seam by firstand second elements each extending in a respective plane intersectingtransversely the plane of the seam, comprising an electrode having a tipfrom which an arc is established, a track generally extending along thelength of the seam, means mounting the welder in engagement with thetrack for movement along the track, and means'moving said welder alongsaid track to weld said seam from said first element to said secondelement while maintaining the electrode tip at a substantiallyconstant'distance from the seam, said means for moving comprising,

means positioning said welder in a first position to di-.

rect said electrode at an acute angle to the plane of the seam at saidfirst end element to initiate said weld, means moving said welder whilewelding from said first position through a second position in which saidelectrode is directed normal to the plane of the seam, and meanspositioning said welder in a third position to direct said electrode atan acute angle to the plane of the seam at said second end element tofinish the weld.

2. An arc welder according to claim 1, in which the second elements.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Inventor-(s) chPloetz et 8.1.

It is certified that error appears in the above-identified patent I andthat said Letters Patent are hereby corrected as shown below:

Column LL, lines 25, 26 (claim 3) delete "to effect said changing of theorientation" Signed and sealed this 18th day of June 197E."

' (SEAL) Attest:

EDWARD MTLET'CHER R. c; MARSHALL DANN' Attesting Officer Commissioner ofPatents ORM PO- I'IOSO (10-69) USCOMM-DC 60376-P69 I v u.s. GOVERNMENTramrmc OFFICE Ins 0-368-584.

, UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, Dted 25,

Inventor(s) Ulrich P106132 61; a1.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column L lines 25, 26 (claim 3) delete "to effect said changing of theorientation" Signedandsealed this 18th day of June 1971;]

(SEAL) v Attest:

EDWARD M.FLETCHER,JR. c. MARSHALL DANN Attesting Officer Commissioner ofPatents )RM PO-lOSO (10-69) UsCOMM-DC 60376-P69 a: us. GOVERNMENT "mumsOFFICE "I! 0-3Gl-38l.

1. An arc welder for welding a workpiece with a seam to be weldedextending in a single plane and abutted at each end of the seam by firstand second elements each extending in a respective plane intersectingtransversely the plane of the seam, comprising an electrode having a tipfrom which an arc is established, a track generally extending along thelength of the seam, means mounting the welder in engagement with thetrack for movement along the track, and means moving said welder alongsaid track to weld said seam from said first element to said secondelement while maintaining the electrode tip at a substantially constantdistance from the seam, said means for moving comprising, meanspositioning said welder in a first position to direct said electrode atan acute angle to the plane of the seam at said first end element toinitiate said weld, means moving said welder while welding from saidfirst position through a second position in which said electrode isdirected normal to the plane of the seam, and means positioning saidwelder in a third position to direct said electrode at an acute angle tothe plane of the seam at said second end element to finish the weld. 2.An arc welder according to claim 1, in which the mounting means isdisplaceable in directions toward and away from the tip for maintainingthe tip at said substantially constant distance from the seam.
 3. An arcwelder according to claim 1, in which the positioning means comprisesmeans for angularly displacing the electrode relative to the mountingmeans to effect said changing of the orientation.
 4. An arc welderaccording to claim 1, in which said track is curved in segments thereofclosest said first and second elements.